The Nakajima A4N was a Japanese fixed-undercarriage biplane on-board fighter from the interwar period. The drive was provided by a single engine Nakajima Hikari 1 with 730 hp. The prototype flight took place in 1934. A year later, serial production began, which lasted until 1940, which resulted in the production of about 220 examples of this aircraft. The deck armament consisted of two 7.7 mm Type 87 machine guns.
The Nakajima A4N was commissioned by the Japanese naval command, which needed a new in-flight fighter capable of replacing older aircraft of this type. In order to reduce research and development time, Nakajima relied on the design of the new machine on another aircraft of its own: the A2N. However, the changes compared to the original were significant: first of all, a completely new engine was used, the aerodynamics was significantly improved, the fuselage cross-section was reduced, and the wingspan was increased. The machine entered service in 1936, replacing the A1N and A2N machines. However, during the operation, many objections were raised as to its performance - especially the maximum speed and the rate of climb. The Nakajima A4N was also quickly withdrawn from service, as from 1940 it was replaced in the line by the Mitsubishi A5M. Nakajima A4N machines took part in the initial period of the conflict in China in 1937-1940 / 1941.
Very often, the date of birth of naval aviation in the Imperial Japanese Navy (IJN for short, Japanese Nippon Kaigun) is March 16, 1923, when Lieutenant Sunishi Kira landed in his plane on board the Hosho aircraft carrier, which, moreover, entered service a year earlier (1922). It should be added, however, that in the course of the 1920s, many Japanese naval officers saw aircraft carriers as supporters of battleships and battleships, bearing in mind the great success of Admiral Heihachiro Togo at Tsushima in 1905. The technical level of the then Japanese on-board aircraft was also not the highest. However, this state of affairs began to change in the 30s of the 20th century, among others, due to the later Admiral Isoroku Yamamoto, who perceived the main weapon in the naval war in aircraft carriers. He was a strong supporter of the development of Japanese on-board aviation, which translated into the construction or modernization of such ships as Kaga, Akagi, Hiryu, Soryu and Zuikaku. Also, Japanese aviation structures not only reached the world leaders, but began to set standards in them, including the famous Mitsubishi A6M Zeke fighter or the Nakajima B5N Kate torpedo plane. This intense development led to the fact that when the war in the Pacific broke out, the IJN had 10 aircraft carriers, on which over 500 on-board machines were based, with well-trained crews. The first months of struggle in the Pacific showed how dangerous this weapon was. It should be remembered, however, that already during that war, the IJN had considerable problems, for example, to replace the A6M Zeke plane on a mass scale or to introduce a successful B5N successor to the line, i.e. the B6N Tenzen torpedo plane. Also, the process of training sea pilots turned out to be flawed and was distanced by the solutions used in the US Navy.